<div>
So it's the senders problem ?
</div>


<div>
<div class="content wysiwyg-content">
Error message ... <br />
<br />
Reporting-MTA: dns; ironport1.vodafone.ie<br />
<br />
Final-Recipient: rfc822;**********@eircom.n<wbr />et<br />
Action: failed<br />
Status: 5.0.0 (permanent failure)<br />
Diagnostic-Code: smtp; 5.4.7 - Delivery expired (message too old) 554-'avas01 Cloudmark Gateway &lt;213.233.128.43&gt; IP rejected [Error Code 250]' (delivery attempts: 0)
</div>
</div>


Error message ... 

Reporting-MTA: dns; ironport1.vodafone.ie

Final-Recipient: rfc822;**********@eircom.net
Action: failed
Status: 5.0.0 (permanent failure)
Diagnostic-Code: smtp; 5.4.7 - Delivery expired (message too old) 554-'avas01 Cloudmark Gateway <213.233.128.43> IP rejected [Error Code 250]' (delivery attempts: 0)

Email error -  Customers email is randomly not accepting emails

Within Internet message handling services (MHS), a message transfer agent or mail transfer agent (MTA) or mail relay is software that transfers electronic mail messages from one computer to another using a client–server application architecture. A MTA implements both the client (sending) and server (receiving) portions of the Simple Mail Transfer Protocol (SMTP). The terms mail server, mail exchanger, and MX host may also refer to a computer performing the MTA function. The Domain Name System (DNS) associates a mail server to a domain with mail exchanger (MX) resource records containing the domain name of a host providing MTA services.